Hydrogen sulphide removal from raw biogas using novel coconut husk and sugarcane bagasse composite biochar adsorbent

Abstract

Abstract The presence of water, hydrogen sulfide (H2S), ammonia, oxygen, nitrogen, and siloxanes in biogas is not desirable for thermal and electrical applications through the engine route. H2S adversely affects engines and fuel cells by causing corrosion on metal components, poisoning catalytic converters, and accelerating wear and tear, compromising performance and longevity. To meet specific quality requirements for diverse applications such as heating, combined heat and power generation, vehicle fuel, and fuel cells, biogas must undergo cleaning and upgrading processes. Using biochar to remove H2S in biogas is a comparatively new technique and can be a promising option for small-scale, decentralized units. Current research primarily investigates the potential of biochar derived from coconut husk (CH) and sugarcane bagasse (SB) for effectively removing H2S from raw biogas within an experimental framework. The selection of a composite material consisting of equal parts CH and SB was based on available literature and material accessibility. The integrated methodology provided comprehensive insights into the performance of biochars in biogas purification. Morphological analysis elucidated the role of pore structure in facilitating H2S removal, while CHNS analysis highlighted the influence of elemental composition on biochar reactivity. Additionally, pH studies underscored the potential for biochar application to mitigate biogas acidity. According to the findings, the biochar from the combination of CH and SB exhibited a removal efficiency of 77.60% for H2S in raw biogas.